With the development of the communication industry, IPTV (Internet Protocol Television) services are applied more and more extensively. In a conventional IPTV service, problems of video encoding and decoding easily result in slow changing of channels, and a phenomenon of packet loss in a network link easily causes an erratic display or blank screen in video playing. The prior art provides a router to solve these problems, on which a value-added service board is arranged to provide video value-added services. One or more value-added service boards form a value-added service server (also referred to as a value-added service group). The server may perform FCC (Fast Channel Changing) and RET (Retransmission, retransmission of a lost packet), thereby improving user experience for videos.
When a client (that is, a set top box) requests FCC and RET, the client sends a request packet to an RRS (Request Routing Server), the RRS routes a primary value-added service server and forwards the request packet to the primary value-added service server routed by the RRS, and then the primary value-added service server communicates with the client directly.
The RRS maintains state information of all value-added service servers by using a heartbeat packet. The RRS sends a heartbeat packet to a value-added service server every 10 seconds. If the RRS does not obtain a response from the value-added service server for three consecutive times, the RRS considers that the value-added service server fails and changes the locally-stored state of the value-added service server to a failed state. Afterward, if the RRS receives a request from the client again, the RRS does not route the failed value-added service server.
When a value-added service board in the value-added service server fails, at least 30 s is required for the RRS to detect the failure of the value-added service server and reroute the request of the client. In this period of time, if a client sends a request packet to the value-added service server, the client will not receive a response immediately, and as a result, the client needs to wait for a long time when requesting FCC and RET, thereby reducing user experience for videos.
The prior art provides a method for setting backup value-added service servers on a router to avoid a long-time waiting of the client when the client requests FCC and RET. A backup value-added service server is formed by one or more value-added service boards. The client stores addresses of all backup value-added service servers. When the client sends a request packet, the client carries the stored addresses of all the backup value-added service servers in the packet. When a value-added service board in the primary value-added service server routed by the RRS fails, resulting in the failure of the primary value-added service server and inability of responding to the request packet, the primary value-added service server forwards the request packet to a backup value-added service server according to the address of the backup value-added service server carried in the request packet, and the backup value-added service server directly communicates with the client, thereby shortening the waiting time of the client in requesting FCC and RET.
In the process of implementing FCC and RET by the backup value-added service servers, the inventor finds that the prior art has at least the following problems: Because the client needs to know the addresses of all the backup value-added service servers in advance, client complexity increases; in addition, because the addresses of all the backup value-added service servers are exposed in a transmission process of the request packet, network security is reduced.